The Magento contacts page is a standalone module: Mage_Contacts, however unlike categories, CMS pages or products, when it comes to the contacts page you are pretty limited by what you can edit from the admin area.

Most, if not all of the mobile devices today will parse telephone numbers found in the content of a web page and convert them into links. The links when clicked by a user will instruct the native phone app to make a call, using the “tel:” protocol.